Is there a link between weight loss drugs and vision loss?

The use of semaglutide for weight loss and diabetes, which is sold under the popular brand names Ozempic and Wegovy, may be linked to an increased risk of developing an eye condition that can lead to vision loss and blindness, according to a study published last week in JAMA Ophthalmology.

Compared with people prescribed other types of medications for type 2 diabetes or weight loss, those taking semaglutide were more likely to develop non-arteritic anterior ischemic optic neuropathy (NAION), which occurs when the optic nerve does not get enough blood supply.

What does this mean for people who use (or want to use) semaglutide or another type of weight-loss drug? The study authors cautioned that this was an observational study, meaning that more research is needed to confirm the extent of the increased risk of eye problems in people with diabetes or taking weight-loss drugs (or if there is a risk at all). Beyond eye health, the weight-loss drug craze has ushered in a host of other health implications, including positive ones.

The JAMA study also didn’t look at the effects of other GLP-1 drugs, including tirzepatide (brand names Mounjaro or Zepbound). This is a similar drug to semaglutide, which came on the market during the Ozempic and Wegovy wave, but it works slightly differently.

Lead author of the study, Dr. Joseph Rizzo, also director of the Neuro-Ophthalmology Service at Mass General Brigham’s Mass Eye and Ear, called the study results “significant but preliminary” in a press release from Mass General Brigham.

“This is information that we haven’t had before and that we need to factor into the conversations between patients and their doctors, especially if patients have other known optic nerve problems, such as glaucoma, or if there is pre-existing significant vision loss from other causes,” Rizzo said.

“Patient safety is a top priority for Novo Nordisk and we take all reports of adverse events related to the use of our medicines very seriously,” Novo Nordisk, which makes Ozempic and Wegovy, said in a statement. The company reiterated the study’s limitations and added that a trial is underway to assess the long-term effects of semaglutide on diabetic retinopathy, a common eye complication that develops in people with diabetes. Previous research has shown that semaglutide can worsen diabetic retinopathy in people who have it, at least early in their treatment.

This is what we know now.

What is NAION?

NAION is a type of eye stroke that causes vision loss or blindness because there is not enough blood flow to the optic nerve. This nerve is located just behind the eye and carries visual information to the brain.

According to Penn Medicine, the exact cause of NAION isn’t completely understood, but it’s more common in middle-aged or older people, and the shape of a person’s optic nerve may even play a role in their risk of eye stroke. Other risk factors for NAION include high blood pressure, diabetes, and obstructive sleep apnea.

Symptoms include loss of vision in the affected eye, especially upon waking in the morning, usually without pain. Other symptoms include blurred vision, color distortion, a gray or dark spot in your field of vision that doesn’t move, light sensitivity and loss of peripheral vision. Vision loss can progress or change over a few weeks but should stop progressing after two months, according to the American Academy of Ophthalmology, an association of ophthalmologists and surgeons. There’s currently no proven treatment for NAION, according to Penn and the AAO, but reducing your vascular risk factors — physical activity, lowering your blood pressure, aiming for healthy blood sugar levels and more — can help prevent it.

If for any reason you experience loss of vision or severe pain around your eyes, seek immediate medical attention.

Read more: 10 Simple Ways to Protect Your Eyes Every Day

Are weight loss and type 2 diabetes treatment good or bad for your eye health?

In addition to NAION, there is an established link between diabetes and eye health. Diabetic retinopathy, a diabetes complication caused by damaged blood vessels in the back of the eye, is the leading cause of blindness in American adults, according to the American Diabetes Association. So it would make sense that treating or controlling diabetes could reduce the risk of diabetic retinopathy, a common cause of vision loss.

The relationship is complicated, however. Some studies have found a potential negative link between eye health and semaglutide, including a 2017 study that found that taking semaglutide could put patients with diabetic retinopathy at increased risk for complications when they first start taking the drug and their blood sugar and insulin levels begin to stabilize. However, in 2023, research presented at the AAO annual meeting found that this link between diabetic eye problems and rapid correction of blood sugar levels may not be as significant as previously thought. Novo Nordisk is conducting a study on the long-term effects of semaglutide on diabetic retinopathy, which is expected to be completed in 2027.

In a press release published Monday about the results of the latest JAMA Ophthalmology study, the AAO noted that previous studies have linked semaglutide to blurred vision, worsening of diabetic retinopathy and macular complications. The eye health organization noted that blurred vision can occur because sudden changes in blood sugar levels can change the shape of the eye, causing blurry vision. The AAO also noted that these changes are typically temporary and go away after a few months.

For some people who take semaglutide or a similar but different class of medications called tirzepatide (Mounjaro or Zepbound) for medically recommended weight loss, their subsequent risk of developing long-term health conditions like diabetes or heart disease (vascular factors like blood pressure also affect eye health) may be lowered in the first place. While some experts have hypothesized that medications like semaglutide may reduce the risk of eye diseases like glaucoma in patients who are at higher risk due to BMI, there isn’t enough evidence at this time to strongly link eye health to weight loss, Optometry Advisor reported.

Should I be concerned about my eyes when taking semaglutide?

The AAO is not currently recommending that people stop taking semaglutide; it noted that semaglutide “has been extensively studied” and was approved for medical use in 2017. The AAO also noted that people in the study developed NAION after their first prescription of semaglutide.

You should always discuss with your doctor which medication is right for you and your health, as the “risk versus benefit” profile is different for everyone. If you have a history of eye disease or other risk factors for NAION, it may be a good idea to contact your healthcare provider to ensure that you continue to benefit from your chosen health management plan.

Learn how to protect your eyes every day, the best foods to eat for healthy vision, and why there may be unexpected links between new weight-loss drugs and health outcomes like fertility and sleep apnea.

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